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Wind Rose
Wed Apr 28, 2004
Listen in RealAudio 
Before compasses became navigational tools in the 13th Century, navigational charts
included a small diagram vital to mariners called the "wind rose." Hi, I'm Bryan Yeaton
for The Weather Notebook.
When early mariners developed navigational aids, they used natural phenomena
including the direction of common winds. The name for the small diagrams used to
indicate the prevailing wind directions looked like the petals of a flower, and thus
became the wind rose.
In early Europe, no distinction was made between compass directions and the winds
emanating from them. Boreas, dressed in a heavy cloak, signified the cold character of
the North Wind so the wind rose pointed North. By 800 during the reign of
Charlemagne, the now familiar compass points, NE, SSW, etc. were adopted.
The most elaborate wind roses had 32 points for the 32 classically named winds, but
16-and 8-point roses were far more legible. Because these charts often had to be read
on heaving ship decks in dim light and bad weather, added colors and symbols aided
in their clarity.
A "fleur de lis" symbol traditionally pointed North, derived from a north arrow and letter
T, for Tramontana, a cool northerly Mediterranean wind. A Maltese cross denoted East.
The eight prime compass points were coloured black, the intermediate half-directions
blue or green, and the quarter winds in red.
Today, a modern variation of the wind rose is an important tool for representing both
wind direction and speed frequencies around the compass, giving it a visual continuity
not found on linear bar charts.
Thanks to our contributing writer, meteorologist Keith Heidorn. To see both ancient and
modern wind roses, blow on over to our website: www.weathernotebook.org. Our show
comes to you through funding from the National Science Foundation and Subaru of
America, Driven By What's Inside.
Today's Links
The windrose and the classical winds
http://web.uflib.ufl.edu/cm/africana/windrose.htm
Reading the Wind Rose
http://www.srh.noaa.gov/bro/roshelp.htm
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